Collapsible container and method of emptying the same



Aug. 10, 1965 R. E. PIERSON GOLLAPSIBLE CONTAINER AND METHOD OF EMPTYINGTHE SAME Filed Nov. 12, 1963 2 Sheets-Sheet l INVENTOR ROBERT E. PIERSONATTORNEY.

Aug. 10, 1965 COLLAPSIB Filed Nov. 12, 1963 FIG. 3.

R. E. PIERSON 3,199,726

LE CONTAINER AND METHOD OF EMPTYING THE SAME 2 Sheets-Sheet 2 F IG. 4.FIG. 5.

INVENTOR ROBERT E. PIERSON ATTORNEY.

United States Patent 3,199,726 QEELLAPSIBLE IGNTAENER AND METl-ifil) 0FEli iPTYmG THE SAls EE Robert E. Pierson, East Greenwich, 12.1.,assignor to United States Rubber Company, New York, N.Y., a corporationof New .iersey Nov. 12, 1963, Ser. No. 323,821

This invention relates to collapsible shipping containers of the typehaving a discharge opening centrally located in one end thereof and,more particularly, to such containers as disclosed in US. Patent No.2,612,924.

In the past, collapsible containers of this type have been emptied bymeans of a frusto-conical, cradle-like device, the arms of which pressagainst the sides of the containers surrounding the discharge opening,thus forcing out the product. Such a device is shown in US. Patent No.2,858,051. Apparatus as disclosed therein, however, is relativelyexpensive to construct and install and has, thus, limited the use ofsuch containers, especially for the transportation and storage of highdensity, comminuted or powdered solid material.

It is, therefore, an object of the present invention to provide acontainer of this type that will be self-unloading, requiring no specialattachments or apparatus. it is a further object of the presentinvention to devise such a container that will utilize present conveyingequipment with little or no modification. It is a still further objectof th present invention to provide an improved container tha willrequire no appreciable modification in existing plant facilities. Afinal object of the present invention is to provide a container thatwill unload directly into processing equipment, thereby greatlysimplifying the handling of any bulk material, especially those of highdensity.

In accordance with these objects, a collapsible fluidtight shippingcontainer as disclosed in the above-mentioned US. Patent No. 2,612,924,which may be made of coated cord fabric and has a cylindrical body andtwo rounded heads, the lower of which has a discharge opening centrallylocated therein, the container also having a entral tie connectionwithin itself between the heads and a removable closure fitting for thedischarge opening, is improved as follows:

An annular bladder layer is attached to the inner wall of the container,the outer edge of the bladder layer being attached to the cylindricalbody portion of the container, the inner edge of the bladder layer beingattached to the lower head of the container at the discharge openingtherein. Also provided is means for introducing gas under pressurebetween the bladder layer and the inner wall of the container, there-byto inflate the bladder in a manner to be hereinafter described. Theinflation is accomplished by means of a fitting mounted in thecylindrical body portion of the container below the line of attachmentor" the outer edge of the bladder layer thereto.

After a container of the improved type is filled with comminuted orpowdered solid material, as, for example, by the method disclosed in US.Patent No. 2,811,173, it is emptied in the following manner. Thecontainer is placed on an unloading stand having an opening therein inregister with the discharge opening in the lower head. A cable isattached from an adjustable overhead support to the eye fitting of thecontainer (see Patent No. 2,858,- 051) and the tension in the cable isadjusted so that the weight of the filled container is supported both bythe unloading stand and by the cable. The closure fitting in the lowerhead is removed, thus allowing the lading to drain from the container bygravity until the flow of material stops.

The bladder layer is then inflated with gas to a pressure aboveatmospheric, thereby to expand the bladder and cause the flow ofmaterial to resume. The pressure is maintained in the bladder until suchresumed flow stops. The pressure is then released in the bladder bydeflating the same or by pressurizing the container proper with thebladder valve open. The process of inflating and deflating the bladderis repeated until the material ceases to flow. For certain types oflading, e.g., Portland cement, the deflation of the bladder is followedby applying vacuum pressure to the inflation fitting.

Other objects and advantages of the present invention will becomeapparent from the following description, when read in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a cross-sectional longitudinal view of a collapsible shippingcontainer of the type disclosed in the above-mentioned US. Patent No.2,612,924, improved as disclosed herein, the dashed lines showing thebladder layer in the inflated position;

FIG. 2 is a bottom view of the container of FIG. 1, showing theremovable closure fitting in place in the discharge opening;

FIG. 3 is a cross-sectional view of the improved container filled with alading of comminuted solid material and shown supported both by theunloading stand and the overhead cable;

FIG. 4 is a cross-sectional view of the container of FIG. 3 after theclosure fitting has been been removed and th lading allowed to draintherefrom by gravity until the flow of material has stopped;

FIG. 5 is a cross-sectional view of the subject container after thebladder has been inflated with gas to a pressure above atmospheric,thereby to expand the same and cause the flow of material to resume;

:FIG. 6 is a cross sectional view of the subject container after thepressure in the bladder has been released by eilating the same; and

FIG. 7 is a cross-sectional view of the subject container shown afterthe bladder has been inflated again, thereby causing the materialremaining in the container to be discharged.

Referring to the drawings and in particular to FIG. 1, there is shown acollapsible container of the type disclosed in the above-mentioned US.Patent No. 2,612,924 and generally designated by the reference letter C.The container is generally formed of two or more plies iii of fiem'ble,rubber-coated fabric and when filled has a generally cylindrical body 11and two rounded heads 12 and 13. The upper head 12 is provided with acentrally located eye fitting L, by which the container may be lifted.by suitable means, such as the cable 14 shown in FIGS.

3-7. A filling opening F and an inflating fitting I are also provided inthe upper head 12 and a discharge opening D is centrally located in thelower head 13. A standard removable closure fitting 15 is provided forthe discharge opening D. A flexible fabric sock or sleeve S is securedto fitting 15 and serves as a spout through which the material may flowfrom the container. A tie-string or other fastening device is normallyprovided to close off 3 sleeve S. When not in use, sleeve S is tuckedinto the container C and is covered by fitting 15.

A central tie connection consisting of steel reinforcing cables W isalso provided as shown in FIG, 1. The cables W are secured to the eyefitting L at the upper head 12 of the container and at spaced points inthe lower head 13. Cables W serve to prevent bulging of the containerheads 12 and 13 and take the load during lifting of the filledcontainer. The lower head 13 of the container is generally reinforcedwith additional plies, as is the material in theupper head 13 around theeye fitting L.

In accordance with the invention, an annular bladder layer 16 isattache-d to the inner surface 17 of the container C. The outer edge 18of the annular bladder layer 16 is attached to the cylindrical body 11of the container C and the inner edge 19 of the bladder layer 16 isattached to the lower head 13 adjacent the discharge opening D and maybe secured by the closure fitting 15, as shown. F or a 125 cubic footcontainer, for example, the bladder layer 16 may be a fabric reinforcedmember 0.106 inch thick, with 0.040 inch rubber liner, and is attachedto the inner surface 17 by means of hinge strips 20 and 21, as shown.The outer edge 13 is preferably located slightly below the verticalmid-plane of container C.

An inflation fitting 22 with a quick-opening ball valve therein ismounted in the cylindrical body 11 below the line of attachment 23 withthe outer edge 13 of the bladder layer 16. Fitting 22 is fixed throughthe outer two plies 10 of the container so that gas under pressure maybe introduced into the bladder, to allow for inflation thereof.

A 125 cubic foot container improved as above described Was filled withpolyethylene pellets and then placed on an unloading stand U, having anopening therein in register with the discharge opening D. A cable 14 wasattached to the eye fitting L from an adjustable overhead support K. Thetension in the cable 14 was adjusted so that the weight of the containerwas supported both by the unloading stand U and, through the cable 14,by the overhead support K. (See FIG. 3.)

The closure fitting 15 was then removed, allowing the 'lading to drainfrom the container by gravity until the flow of material stopped,Approximately 70% of the lading wasremoved in this initial operation.(See FIG. 4.) Bladder layer 16 was then inflated through the inflationfitting 22 using high volume, low pressure (1.5 to 2.0 p.s.-i.g.) air,thereby to expand the bladder, as shown in FIG. 5, and cause the flow oflading to resume. The pressure was maintained in the bladder until theflow of material again stopped. The pressure in the bladder was thenreleased by deflating the same through the quickopening ball valve ininflation fitting 22. (See FIG. 6.) The bladder 16 was then inflatedagain, as shown in FIG. 7, causing the material to resume flow, After atotal of four inflation-deflation cycles, only 2 pounds, representing of1%, of the lading remained in the container. This was easily removed byvacuuming through the emptying sleeve S.

In another trial, the same container was filled to capacity with 8,500pounds of Portland cement and was allowed to compact for five days. Thethus-filled container was then placed on the unloading stand U, again sothat the weight was supported both by the stand and the cable 14. (SeeFIG. 3.) After the closure fitting was removed, the lading was allowedto drain by gravity until the flow of cement stopped; (See FIG. 4.) Thebladder layer 16 was then inflated as before to expand the same andcause the flow of material to resume. (See FIG. 5.) Pressure wasmaintained in the bladder until the flow of material again stopped. Thepressure in the bladder was then released by deflating the same throughthe quick-opening ball valve in inflation fitting 22. (See FIG. 6.)Vacuum pressure was then applied to the blad- A dear layer 16 throughinflation fitting 22, The inflationdeflation cycle was repeated a totalof siX times, with vacuum deflation between cycles, and at the end ofthe last cycle the amount of Portland cement remaining was 28.5 pounds,or of 1% of the initial 8,500 pound load.

The bladder could also be deflated by inflating the entire containerthrough fitting I with the valve in fitting 22 Also, bladder layer 16may be provided with small air permeable sections therein, so that forsome types of lading air can be introduced into the lading to aerate itas said bladder layer is inflated. This will assist the lading to emergefrom the container through the discharge opening D.

Frorn the above description it can be seen that I have disclosed animproved container and method of emptying the same. While a certainpreferred form of the invention has been shown and described, it is tobe understood that this is for the purpose of illustration only and thatchanges and modifications can be made therein without departing from thespirit and scope of the invention.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. In a collapsible fiuid-tight shipping container formed primarily ofcoated fabric and having a cylindrical body portion and two roundedheads, the lower of said heads having a dischange opening centrallylocated therein, said container having a central tie connection withinitself between said heads and a removable closure fitting for saiddischarge opening, the improvement comprising:

an annular bladder layer attached to the inner wall of said container,

the outer edge of said bladder layer being attached to said cylindricalbody portion of said container, the inner edge of said bladder layerbeing attached to said lower head of said container adjacent to salddischarge opening therein; and means for introducing gas under pressurebetween said bladder layer and said inner wall of said container.

2. The improvement described in claim 1, in which said gas introducingmeans comprises an inflation fitting mounted in said cylindrical bodyportion below the line of attachment of said outer edge of said bladderlayer thereto.

3. The method of emptying a collapsible fluid-tight shipping containerfilled with a lading of comniinuted solid material;

said container having a cylindrical body portion and two rounded heads,the lower of said heads having a discharge opening centrally locatedtherein, the upper of said heads having an eye fitting centrally locatedthereon; said container having a removable closure fitting for saiddischarge opening, a central tie connection between said eye fitting andsaid lower of said heads, and an annular inflatable bladder layerattached to the inner wall of said container, the outer edge of saidbladder layer being attached to said cylindrical body portion of saidcontainer, the inner edge of said bladder layer being attached to saidlower head of said container adjacent said dis charge opening therein;said container having means for introducing gas under pressure betweensaid bladder layer and said inner wall of said container, comprising:

placing said container on an unloading stand having an opening thereinin register with said discharge opening; attaching a cable from anadjustable overhead support to said eye fitting; adjusting the tensionin said cable so that the weight of said container is supported both bysaid unloading stand and said cable; removing said closure fitting;

allowing said lading to drain from said container by gravity until theflow of material stops;

in lating said bladder layer with gas to a pressure above atmospheric toexpand the same and cause the flow of material to resume;

maintaining said pressure in said bladder layer until said flow stops;

releasing said pressure in said bladder layer by deflating the same;

and repeating said inflating and deflating of said 10 is deflated byopening said gas introducing means and inflating said container.

References Cited by the Examiner UNITED STATES PATENTS 2,755,143 7/56Cunningham 222193 X 2,858,051 10/58 Cunningham 222105 X 3,055,553 9/62Mapes et a1. 222-95 3,058,498 10/62 Vogt 2221 X FOREIGN PATENTS 624,2867/61 Canada.

RAPHAEL M. LUPO, Primary Examiner.

1. IN A COLLAPSIBLE FLUID-TIGHT SHIPPING CONTAINER FORMED PRIMARILY OFCOATED FABRIC AND HAVING A CYLINDRICAL BODY PORTION AND TWO ROUNDEDHEADS, THE LOWER OF SAID HEADS HAVING A DISCHARGE OPENING CENTRALLYLOCATED THEREIN, SAID CONTAINER HAVING A CENTRAL TIE CONNECTION WITHINITSELF BETWEEN SAID HEADS AND A REMOVABLE CLOSURE FITTING FOR SAIDDISCHARGE OPENING, THE IMPROVEMENT COMPRISING: AN ANNULAR BLADDER LAYERATTACHED TO THE INNER WALL OF SAID CONTAINER THE OUTER EDGE OF SAIDBLADDER LAYER BEING ATTACHED TO SAID CYLINDRICAL BOCY PORTION OF SAIDCONTAINER, THE INNER EDGE OF SAID BLADDER LAYER BEING ATTACHED TO SAIDLOWER HEAD OF SAID CONTAINER ADJACENT TO SAID DISCHAREG OPENING THEREIN;AND MEANS FOR INTRODUCING GAS UNDER PRESSURE BETWEEN SAID BLADDER LAYERAND SAID INNER WALL OF SAID CONTAINER.